This invention generally relates to pressure feeding devices and more particularly to a device for propelling or dispensing a material from a container having a source of gas or propellant vapor under super atmospheric pressure therein and an outlet valve having a spray orifice through which the material is discharged.
One well known form of this type of device is the common household aerosol type dispensing container which is adapted to dispense a product such as, for example, an insecticide, deodorant, perfume or the like in a spray form when a valve is manually opened. A pressurized gas or vapor disposed within the dispensing container and usually mixed with the material to be dispensed therefrom, upon opening of the outlet valve to the lower atmospheric pressure surrounding the outside of the container, causes such material to be discharged in a spray through the outlet valve. The rate of flow or delivery rate through the outlet valve is generally dependent upon a variety of factors such as the viscosity and density of the mixture or product being dispensed, the pressure in the dispensing container, and the design of the valve mechanism. Within the valve design, it is the passageway therein having the smallest cross-sectional area or diameter which essentially determines the rate of delivery which the valve portion of the dispensing container will provide. This passageway may be disposed in the lower end of the container in the valve stem or diptube, internally in the body structure, or in the actuating button at the mouth of the container for opening the valve, as desired, and in any one of these positions still controls the valve delivery rate.
Much difficulty has heretofore been experienced in the manufacture of aerosol dispensing containers of the type described, especially in providing and maintaining very small passageways having diameters on the order of thousandths of an inch which are necessary in many cases for providing the most suitable flow rate through the valve of the dispensing container. Capillary tubes have been used for the purpose, but the disadvantage even with these has been the limitations from a manufacturing standpoint of providing passageways of sufficiently small diameters and including the similar narrow tolerances demanded thereby.